In many prior art production systems, metering blades, doctor blades, or metering rollers are required to be positioned above a rotating cylinder at a very specific, controlled distance. Such systems include printing or inking operations, application of ink material to elongated, continuous webs, as well as in the textile industry for the application of various dyes or insulating material to elongated continuous webs of material.
In spite of the wide variety of applications and systems in which precise control of metering blades, doctor blades, or metering rollers relative to a fixed bed or rotating drum is required, no prior art system has been able to achieve a reasonably priced, precision metering blade positioning system.
In general, most prior art systems incorporate a single drive motor typically connected near one end of the doctor blade, metering blade, or metering roller with said single motor being employed to move the entire metering blade or roller into the desired position. However, due to typical inherent problems, such as gear train backlash, precise control over the gap between the metering blade or roller and the fixed roller, along the entire length thereof, has been impossible to obtain, especially in situations where precision is mandatory.
In an attempt to satisfy the increasing need for obtaining a precise, controlled gap between a metering blade or metering roller, and the coating roller with which it is associated, more sophisticated, electronic distance-measuring systems were employed. However, all of these prior art systems suffer from the universal drawback that the measuring system is mounted at one end of the metering blade or roller, with the opposed end being moved simultaneously therewith. As a result, these prior art systems have failed to meet the requisite need for obtaining precise gap distances along the entire length of the metering blade.
Another prior attempt to satisfy this need for precise gap control was the use of hydraulic systems to move the metering blade or roller to the desired position. These systems typically use a single, central piston cylinder to controllably move both ends of the metering blade or roller to the desired position. However, due to leakage problems and pressure control difficulties, these hydraulic prior art systems have been completely incapable of attaining or maintaining prece gap distances between a metering blade and its accompanying roller.
Consequently, it is a principal object of the present invention to provide a metering blade or roller positioning system which is capable of repeatably and reliably positioning metering-blades with a desired, precise gap width which extends along the entire blade length.
Another object of the present invention is to provide a metering blade or roller positioning system having the characteristic features described above which is capable of accurately positioning the metering blade or roller within 0.0005 inches of the desired position along the entire length of the blade.
Another object of the present invention is to provide a metering blade or roller positioning system having the characteristic features described above which is capable of automatic as well as manual control.
A further object of the present invention is to provide a metering blade or roller positioning system having the characteristic features described above which is capable of being operated efficiently in any desired environment, without fear of difficulty or adverse impact on the processes being conducted.
Another object of the present invention is to provide a metering blade or roller positioning system having the characteristic features described above which is explosion-proof and intrinsically safe in operation.
Other and more specific objects will in part be obvious and will in part appear hereinafter.